public class Duck {
    protected String color;
    protected double heavy;

    public Duck(String color, double heavy) {
        this.color = color;
        this.heavy = heavy;
    }

    public void fly() {
        System.out.println("鸭子在飞行");
    }

    public void quack() {
        System.out.println("鸭子在叫");
    }
}